It's probably defensive to some extent on both sides. A lot of atheists I've run into seem to be out to prostlytize as well--they are basically evangelists for the atheist way of thinking. Religiously atheist, you might say. They're looking for opportunities to assert the atheist message. And I've read some pretty darn hateful things said about Christianity right here in these forums, and just chalking it up to be "defending" or "kicking back" doesn't really fly. Who knows who threw the first punch? It's to the point that it doesn't really matter anymore, because both sides should be showing respect.
Label: Non-Sarcastic